FIG. 22 and FIG. 23 are drawings for describing a conventional thermoelectric apparatus, in which FIG. 22 is a cross-sectional view of the thermoelectric apparatus and FIG. 23 is a cross-sectional view taking along line X--X of FIG. 22.
As is illustrated in FIG. 22, a group 102 of thermoelectric elements, which are composed of electrodes and P-type and N-type semiconductor layers, is held between a heat-absorbing-side insulating substrate 100 and a heat-dissipating-side insulating substrate 101 both of which are made of ceramics such as alumina.
A heat-absorbing member 103 carrying heat-absorbing fins or the like attached thereto is arranged on an outer surface of the heat-absorbing-side insulating substrate 100. On an outer surface of the heat-dissipating-side insulating substrate 101, a flow-passage-forming member 104 is arranged with openings thereof directed toward the substrate 101. Inside the flow-passage-forming member 104, a continuous flow passage is formed so that water 105 as a heat transfer medium is allowed to tortuously flow along the outer surface of the substrate 101 from an end of the flow-passage-forming member toward an opposite end thereof. A supply pipe 107 is disposed in the vicinity of the one end of the flow-passage-forming member 104, while a drain pipe is arranged in the vicinity of the opposite end of the flow-passage-forming member.
A predetermined current is fed to the thermoelectric element group 102 and, at the same time, the water 105 is caused to flow into the flow-channel-forming member 104 through the supply pipe 107. Heat absorbed by the heat-absorbing member 103 is transferred to the heat-dissipating-side insulating substrate 101 via the heat-absorbing-side insulating substrate 100 an the thermoelectric element group 102. By allowing the water 105 to tortuously flow along the outer surface of the substrate 101, the water absorbs heat from the substrate 101. The water 105 is then discharged out of the system through the drain pipe 108, whereby cooling takes plate on a side of the heat-absorbing member 103.
Its relevant techniques are found, for example, in Japanese Language Laid-Open (Kokai) Publication (PCT) No. HEI 6-504361, Japanese Patent Application Laid-Open (Kokai) No. HEI 5-322366 and Japanese Patent Application Laid-Open (Kokai) No. HEI 5-343750.
Incidentally, these conventional thermoelectric apparatuses are accompanied by a problem in that sufficiently high thermoelectric conversion ability is still unavailable from them.
The present inventors have proceeded with an investigation about this problem. As a result, it has been found that there is a problem especially in the manner of allowing a heat transfer medium to flow through such thermoelectric apparatuses. Described specifically, it has been found that, because a heat transfer medium is allowed to flow simply in a tortuous pattern along a surface of an insulating substrate in each conventional thermoelectric apparatus, the thermal conductance between the heat transfer medium and the insulating substrate is low, thereby failing to obtain any sufficient thermoelectric conversion ability.
An object of the present invention is to overcome such a drawback of the conventional art and hence to provide a thermoelectric apparatus which is excellent in performance and has sufficiently high thermoelectric conversion ability.